Iodoform gives a precipitate with AgNO3 on heating but chloroform does not because -

Options

A. Iodoform is ionic
B. Chloroform is covalent
C. C–I bond in iodoform is weak and C–Cl bond in chloroform is strong
D. None

Answer

To understand why iodoform gives a precipitate with AgNO3 on heating while chloroform does not, we can break down the explanation into several steps:

### Step 1: Identify the Compounds
- **Iodoform** has the chemical formula **CHI3**.
- **Chloroform** has the chemical formula **CHCl3**.

### Step 2: Reaction with Silver Nitrate (AgNO3)
- When iodoform (CHI3) is heated with AgNO3, a reaction occurs that leads to the formation of **silver iodide (AgI)**.
- When chloroform (CHCl3) is heated with AgNO3, it theoretically could form **silver chloride (AgCl)**.

### Step 3: Solubility of the Products
- **Silver iodide (AgI)** is known to have very low solubility in water, which means it will precipitate out of the solution.
- **Silver chloride (AgCl)**, on the other hand, is more soluble in water. When heated, it remains in its ionic form (Ag+ and Cl- ions) and does not precipitate.

### Step 4: Bond Strength and Ion Formation
- The bond between carbon and iodine (C-I) in iodoform is weaker than the bond between carbon and chlorine (C-Cl) in chloroform.
- This weaker bond in iodoform allows it to break more easily upon heating, releasing **iodide ions (I-)** into the solution.
- In contrast, the stronger C-Cl bond in chloroform does not break as easily, so it does not release chloride ions (Cl-) when heated.

### Step 5: Conclusion
- Therefore, when iodoform is heated with AgNO3, it produces iodide ions that react with silver ions to form a yellow precipitate of silver iodide (AgI).
- Chloroform does not produce chloride ions upon heating, so no precipitate of silver chloride (AgCl) is formed.

### Final Answer
Iodoform gives a precipitate with AgNO3 on heating because it forms iodide ions (I-) that precipitate as silver iodide (AgI), which is insoluble. Chloroform does not give a precipitate because it does not release chloride ions (Cl-) upon heating, and any silver chloride formed remains soluble.

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